Machine for deforming sheet metal from the flat state into a tubular form



Sept. 15, 1970 E. 1. ROBINSKY 3,528,272

MACHINE FOR DEFOBMING SHEET METAL FROM THE FLAT STATE INTO A TUBULAR FORM Filed Oct. 28. 1968 2 Sheets-Sheet 1 Sept. 15, 1970 E. RQBINSKY 3,528,272

MACHINE FOR DEFQRMING SHEET METAL FROM THE FLAT STATE I INTO A TUBULAR FORM Filed Oct. 28. 1968 2 Sheets-Sheet 2 United States Patent O US. Cl. 72-146 9 Claims ABSTRACT OF THE DISCLOSURE A machine is provided which will automatically stress a thin resilient metallic sheet to coil about its Longitudinal axis to form a tube which will flatten out when wound into a roll and will resume the tubular shape when unwound. The metallic sheet which may conveniently be wound into a roll is slowly unwound to move over a compressible pad that is supported on a fixed horizontal table. A scribing tool is reciprocated back and forth across the sheet deforming the sheet progressively by pressing a narrow portion thereof into the compressible pad. The hardness and thickness of the compressible pad, the pressure applied by the scribing tool, the shape of the tool and the type and thickness of the metallic sheet determine the resulting curvature imparted to the sheet. By uniformly varying the pressure in a wave cycle from a maximum to zero to maximum, longitudinal corrugations may also be formed in the metallic sheet.

BACKGROUND OF THE INVENTION In my US. Pat. No. 3,252,173 dated May 24, 1966, I described a portable roll up structure having the longitudinal edges which are pre-stressed to form into tubes when unwound from a roll and which will flatten out when rolled-up. In my US. Pat. No. 3,385,397 dated May 28, 1968. I described an extensible retractile structure which employed tubular rails of pre-stressed steel to the end that the structure could be wound up into a roll, the tubular rails automatically flattening when entering the roll.

OUTLINE OF THE INVENTION This invention relates to a machine for mechanically stressing the resilient metallic sheets to form into a tube or tubes when unwound from a roll or flatten out when wound up into a roll. A further feature of the machine is that it can be readily adapted to form longitudinal corrugations to increase the rigidity of the tubular form of the sheet or form corrugations on a flat continuous sheet.

The machine for stressing a resilient thin metallic sheet about its longitudinal axis comprises:

(a) a support table having support means at each end for rotatably supporting a roll of metallic sheet;

(b) drive means for rotating one of said rolls, whereby the metallic sheet is unwound from one support means and wound onto the other support means;

(c) a fixed bed plate of substantial length, said. plate having a width substantially the same as the width of the metallic sheet;

(d) a compressible pad supported on said plate over which said sheet travels;

(e) hold-down means holding said metallic sheet against said compressible pad during its travel thereover; (f) a scribing tool mounted for continuous back and forth movement across said metallic sheet;

(g) drive means connected to said tool for effecting the reciprocation thereof; and

(h) a biasing means acting on said tool in a direction to force it against said metallic sheet whereby the said metallic sheet is deformed and stressed to coil about its longitudinal axis when released from the hold-down means.

The method for stressing a resilient thin metallic sheet to coil about its longitudinal axis comprising the steps of:

(a) slowly moving the metallic sheet longitudinally over a rigidly supported compressible pad;

(b) firmly holding the metallic sheet against the pad;

and

(c) pressing a scribing tool against the metallic sheet and drawing it back and forth across the moving sheet to thereby progressively stress the sheet to coil about its longitudinal axis.

DESCRIPTION OF THE INVENTION The method and machine for stressing the metallic sheets is set forth in the following disclosure, aided by the accompanying drawings in which:

FIG. 1 is a side elevation of the machine, with the front face of the support table removed, constructed in accordance with the invention;

FIG. 2 is a plan view of the machine shown in FIG. 1;

FIG. 3 is a transverse cross-section to show a machine constructed to form longitudinal corrugations;

FIG. 4 is an enlarged fragmentary view showing an alternative construction of the scribing tool;

FIG. 5 shows a metallic sheet which has been processed according to the invention to form an uncorrugated tube;

FIG. 6 shows a metallic sheet which has been processed by the machine illustrated in FIG. 3 to form a corrugated tube.

The machine illustrated in FIGS. 1, 2 and 3 comprises a supporting table 10 of substantial length which is provided with axles 11, 12, one at each end, on which are mounted bobbins 13, 14, the bobbin 14 being driven through motor 15 and belt 16; a fixed bed plate 17 of substantial length and mounted within the sides of the table approximately centrally between the bobbins 13, 14. The fixed bed plate 17 supports an endless compressible pad 18, the pad 18 being in the form of a belt carried on free wheeling drums 19, 20 which permits progressive movement of the pad 18 with the moving sheet during deforming of the sheet.

A roll of flat metallic sheet 21 is wound onto bobbin 13 and rotatably mounted on axle 11, the metallic sheet being fed over the compressible pad 18 where it is deformed as hereinafter described and then rewound onto the bobbin 14. During the passage of the sheet 21 over the compressible pad 18, it is guided and held against lateral displacement by guides 22, 23, 24, 25 which are mounted in spaced apart'relationship, in pairs, on opposite sides of the transverse centre line of the table.

The deforming means which stresses the resilient thin metallic sheet so that it will coil about its longitudinal axis when released from a rolled-up state comprises a deforming head, generally indicated by the number 26 which is supported by the table, at about the transverse centre line of the table for reciprocating movement across the sheet as herein described. The deforming head 26 is mounted substantially midway between the axles 11, 12 and is supported for this movement on tracks 27, 28 which are carried by the table. In the present modification, the tracks 27, 28 also carry tracks 29, 30 running in the same direction as the tracks 27, 28 but at a slightly higher elevation.

The deforming head 26 comprises a main body portion 31 which is mounted on the tracks by means of a carriage which includes the wheels 32, 33, 34 and 35. The body portion 31 adjacent the sheet 21 is provided with a grooved shoe 36. The deforming head is provided with a scribing tool consisting of a wire 37 made of metal or plastic, which is wound on bobbins 38, 39 carried by the main body portion, the bobbin 39 being slowly driven by motor 40. The wire 37, as will be seen from the drawings, is threaded through the grooved shoe 36 and at that point forms the scribing point 40. This arrangement is intended to extend the life of the scribing point by continual replacement of same.

Mounted on the underside of each of the tracks 27, 28 are hold down devices 41, the lower edges of which rest against the top of the sheet 21 and restrain the sheet against coiling while passing under the scribing point. The deforming head is biased in the direction to press the scribing point into the sheet by weights 42. The diameter of the wire 37, the length of the shoe, the weight of the biasing means, hardness and thickness of the pad 18, and the physical properties of the sheet being deformed determine the resulting curvature in the sheet to be deformed.

The deforming head is reciprocated by piston 43 having a piston rod 44 which is operatively connected to the deforming head at 45.

The machine illustrated in FIGS. 1 and 2 operates in the following manner. The metallic sheet 21 is fed in the direction indicated by the arrow under the scribing point 40' and, after being deformed is rewound on the bobbin 14. Simultaneously with the movement of the sheet 21, the deforming head 26 is reciprocated transversely with the scribing point 40 pressing the sheet into the compressible pad. This deforms the metallic sheet progressively and will apply a stress which will cause the sheet to coil into a tubular form when it is released from the roll form wound on spindle 14.

It will be obvious, of course, if the tube is required immediately in its finished form, the rewinding of the sheet into a roll can be dispensed with.

When it is desired to produce a tube having longitudinal corrugations, tracks similar to the tracks 29, 30 can be provided with cam surfaces. For example, FIG. 3 shows one of the tracks 28a formed with cam lobes 46 to provide a continuous wave formation on the upper surface of the track 28a from one end to the other. The wheels 32, 33 serve as cam followers, one for each track. The wheels 32, 33 will alternatively lift and lower the deforming head so that the pressure of the scriber point on the metallic sheet alternates between a maximum and zero pressure. The result will be a corrugated tube shown in FIG. 7.

FIG. 4 shows an alternative structure for the deforming head and the soft compressible pad. In FIG. 4, the compressible pad 48 is mounted on a rotatable cylindrical drum 49 which is in axial alignment with the centre line of the deforming head. The shoe 36 of FIG. 1 is replaced by a freely rotatable pulley 50. In both the structures shown in FIG. 1 and FIG. 4, the compressible pad moves freely with the sheet to protect the pad against damage during the deforming operation.

What I claim is:

1. The machine for stressing a resilient thin metallic sheet to coil about its longitudinal axis comprises:

(a) a support table having support means at each end for rotatably supporting a roll of metallic sheet;

(b) drive means for rotating one of said rolls, whereby the metallic sheet is unwound from one support means and wound onto the other support means;

(c) a fixed bed plate of substantial length, said plate having a width substantially the same as the width of the metallic sheet;

(d) a compressible pad supported on said plate over which said sheet travels;

(e) hold-down means holding said metallic sheet against said compressible pad during its travel thereover;

(f) a scribing tool mounted for continuous back and forth movement across said metallic sheet;

(g) drive means connected to said tool for effecting the reciprocation thereof; and

(h) a biasing means pressing said tool against said metallic sheet whereby the said metallic sheet is deformed and stressed to coil about its longitudinal axis when released from a rolled-up state.

2. A machine according to claim 1 in which the biasing means includes means for varying the pressure on the sheet at uniformally spaced intervals during the backand-forth movement of the tool to thereby form uniformally spaced longitudinal corrugations in the sheet.

3. A machine according to claims 1 or 2 in which said scribing tool comprises:

(i) a pair of rails mounted above and transverse to the longitudinal axis of the metallic sheet;

(ii) a wheeled carriage mounted on the rails for backand-forth movement thereover;

(iii) a scriber head mounted on said carriage; and

(iv) a scriber point carried by the scriber head and positioned to press against said metallic sheet and deform same during the back-and-forth movement.

4. A machine according to claim 3 in which said scriber point comprises a pair of wire bobbins on which is wound a supply of wire, means driving one of said bobbins to slowly wind the wire from one bobbin to the other and a wire guide member positioned between the bobbins and located to press said wire against said me-. tallic sheet. 5. A machine according to claim 4 in which the guide wire member is a pulley having a circumferential groove in which the wire is engaged and held against lateral displacement under operating conditions.

6. A machine according to claim 4 in which the guide wire member is a fixed shoe having a longitudinally extending fixed groove facing said metallic sheet, said wire being engaged in said groove and held against lateral displacement under operating conditions.

7. A machine according to claim 3 in which the means for varying the pressure of the pressure member cornprises a plurality of uniformally spaced cam lobes formed on the rail surfaces over which the wheels of the carriage travel whereby the pressure of the scriber point on the metallic sheet alternates between a maximum and zero pressure.

8. The method for stressing a resilient thin metallic sheet to coil about its longitudinal axis comprising the steps of:

(a) slowly moving the metallic sheet longitudinally over a rigidly supported compressible pad;

(b) firmly holding the metallic sheet against the pad;

and

(c) pressing a scribing tool against the metallic sheet and drawing it back-and-forth across the moving sheet to thereby stress the sheet progressively to coil about its longitudinal axis.

9. The method for stressing resilient thin metallic sheets according to claim 8 in which the scribing tool is pressed against the sheet with a uniformally spaced undulating pressure to thereby produce longitudinal corrugations in the said sheet.

References Cited UNITED STATES PATENTS 6/1964 Green 72168 X 3/1969 Amthor et al 72465 X US. Cl. X.R. 72l76, 371 

